|Publication number||US7106958 B2|
|Application number||US 10/820,579|
|Publication date||Sep 12, 2006|
|Filing date||Apr 8, 2004|
|Priority date||Nov 10, 2003|
|Also published as||DE10352394A1, DE10352394B4, DE502004006175D1, EP1529485A1, EP1529485B1, US20050100333|
|Publication number||10820579, 820579, US 7106958 B2, US 7106958B2, US-B2-7106958, US7106958 B2, US7106958B2|
|Inventors||Harald Kerschbaumer, Gottfried Rohner, Walter Pokorny|
|Original Assignee||Ivoclar Vivadent Ag|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (16), Referenced by (21), Classifications (14), Legal Events (3)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application claims foreign priority benefits under 35 U.S.C. §119 from German patent application Ser. No. 103 52 394.4 filed Nov. 10, 2003.
The present invention relates to an intra-oral camera as well as a method for using such an intra-oral camera.
The use of intra-oral video and/or picture taking-systems (hereinafter designated as an “intra-oral camera system” and as a camera device), has strongly increased over the recent years in the area of use of dental medicine. Such systems are deployed in a variety of settings as well as in situations in which a dentist desires to point out and display certain features of a patient's mouth. These intra-oral camera systems are more and more frequently the passport to complex diagnostic and treatment planning. With respect to such systems, it has been shown that approximately 30% of the practicing dentists between ages 35 and 54 own intra-oral camera systems and use such. It is expected that this percentage will increase as confidence is gained in the use of such systems, according to Dental Procedures Report, pages 22 to 24, February 1995.
Intra-oral camera systems are often deployed in connection with dental restoration efforts. Many people opt nowadays for clinical intervention to improve, via restorative processes, their smiles and appearance. In most such processes, modification of the form or shape of the tooth, the position of the tooth, and/or the color of the tooth are involved.
A necessary step in connection with the modification of the color of a tooth of a patient is the determination of the color shade of the respective tooth. In this connection, for example, the color of the teeth of those patients who are interested in a whiter, beaming smile are evaluated so that a comparison between the appearance of the teeth prior to the restorative treatment and the appearance of the teeth after the restorative treatment can be undertaken. The determination of the color shade is even more important for those persons who require replacement teeth; it is the goal of such restoration processes to achieve a natural appearance of the replacement teeth. For this reason, it is important to properly identify the color shade of the respective tooth so that the new restoration piece can be approximated to the original tooth or teeth.
Typically, a picture of a tooth is taken and a color shade analysis system is used in order to receive suitable information concerning the color shade and the tooth form. The users of such systems often find it difficult to properly orient the intra-oral camera. A correct axial orientation and proper picture taking alignment is, however, of significant importance for enabling the use of analysis software which then processes the picture of the tooth to determine the color shade of the respective tooth.
The size of the region of interest, the size of the camera, the intra-oral location of the area of interest, and, as well, other factors, render difficult the relevant analysis, as such factors influence the two-dimensional picture that is taken. In this connection, it may occur that less than desirable pictures are taken, such as pictures in which a to-be highlighted area of the respective tooth has been cut out or pictures of teeth that are not of interest.
A further disadvantage of such systems, which involve picture taking via a hand-held camera, is that even relatively small hand movements (such as, for example, the movement of a finger to press the shutter actuator) can cause a considerable deviation of the camera from its proper picture taking orientation.
Frequently, the taking of a satisfactory picture of an intra-oral item of interest requires, in connection with such known conventional systems, repeated attempts and/or the burdensome deployment of various devices.
The present invention offers a solution to the challenge of providing an intra-oral camera as well as a method of using such an intra-oral camera for producing an axially aligned picture of an intra-oral item of interest which permits a rapid taking of picture, whereby burdensome usage requirements are avoided without, however, suffering any diminishment in the quality of the picture that is taken.
In accordance with the present invention, a computer controlled picture taking positioning of the intra-oral camera properly positions the camera for taking pictures of objects of interest. The proper picture taking position of the camera ensures that the picture of an intra-oral object or an area of interest such as, for example, a tooth of a patient, is taken in the desired size, at the desired angle, and at the desired location. Drawing upon experience, one can set or adjust beforehand all relevant picture taking parameters so that an error-causing hand movement is foreclosed. The devices for setting the proper picture taking position can use a light source emitting a substantially pinpoint light which is oriented toward the respective object of interest that just then, at that instance, is viewable via the viewfinder of the camera or that is oriented toward the camera. In connection with pinpoint light sources, a laser diode or another light source can be deployed which produces a point of light or a limited light beam region. The pinpoint light source can also be integrated into the camera.
In connection with pinpoint-type light sources, it is to be understood that this concept does not relate to the form of the light source itself but, rather, to the type of light emitted by the light source and directed as a light beam onto an area to be illuminated. This light beam is preferably a pinpoint light beam—that is, the light beam is substantially annular—whereupon a light beam of this type can also be characterized as a point of light or as a light patch.
The light emitted from a pinpoint light source, which is, in turn, reflected by an object of interest, is evaluated, in accordance with the present invention, so as to verify whether a camera is directly oriented toward a respective location a picture of which is desired. A selectively cropped camera frame portion is used to evaluate the orientation of the camera. The selectively cropped camera frame portion can be selected such that it is suitable in shape and size relative to the respective point of light that is produced by the irradiation of the relevant object or area of interest by the pinpoint light source. The distance between the camera and its target is preferably a predetermined distance or spacing which can be set or adjusted via the use of a short standoff tube or a standoff retainer.
In accordance with one embodiment of the present invention, the user can be provided with information which specifies the distances at which the pictures should be taken.
In accordance with the present invention, it is provided that a geometric pattern such as a grating, raster points, an intensity distribution or the like—that is, a two-dimensional reference system—is imposed or overlaid on the picture in order to determine the size of the angle deviation in connection with the orientation of the camera and, at the same time, to provide information for undertaking a correction of the angle deviation. The correction can be effected via a corresponding signal to effect “trimming” in the relevant direction. It is also possible to emit an optical or acoustic signal that indicates that the camera is now exactly aligned or on target.
In an embodiment of the present invention, it is provided that actuation of the shutter actuator for the camera can only be undertaken if a picture target alignment has been performed. It is also possible to use the picture target alignment as a type of trigger signal for actuation of the camera so that the taking of the picture upon pressing of the camera shutter actuator can only be effected if the picture target alignment has been performed.
With regard to the concept of a point of light, it is to be understood that this concept has reference to a limited lighted or illuminated region. Typically, a light patch created by light emitted from a pinpoint light source has an annular shape or configuration, wherein the highest intensity thereof is in the central portion of the light patch. A light region or light patch of this type is herein designated as a point of light.
The selectively cropped camera frame portion, which is used for evaluating the camera orientation, is, in an advantageous embodiment of the present invention, used in connection with evaluating sub-areas into which the selectively cropped frame portion has been subdivided or partitioned, such sub-areas being herein designated as “subdivisions.” The content of the subdivisions (for example, their light properties) can be evaluated in order to verify whether the camera is substantially in proper picture taking alignment with respect to the respective area to be photographed. In this connection, two or more subdivisions are compared with one another. The subdivisions can, for example, be grating fields comprised of the previously noted gratings. It is also possible to establish a gradation of the intensity values of the light intensities among the subdivisions.
The devices for setting the proper picture taking position can, for example, have targeting software associated therewith to generate an indication that the camera is substantially in proper picture taking alignment with the respective area to be photographed, wherein the confirmation of such alignment is based upon information concerning the light produced by the pinpoint light source. The indication can be an audible or visible indication. For example, a green light can illuminate in a designated area of a display of a camera to indicate a proper picture taking alignment. Correspondingly, a picture of the instantaneous camera view can be taken and automatically or manually stored. In the event that such is desired, a system of this type can be so configured to permit the user to chose an automatic picture taking mode in which the camera will take a picture automatically.
In an advantageous embodiment of the present invention, the intra-oral camera is automated in order to deliver a fast, precise, and reliable picture of an intra-oral object of interest. A pinpoint light source such as, for example, a laser diode, serves to verify when a camera in an intra-oral camera system has assumed the desired position for the taking of a picture.
The intra-oral camera system automatically takes the picture without requiring user intervention, provided that certain criteria are fulfilled. In this connection, the picture is subdivided into selectively cropped camera frame portions each of which is evaluated. The selectively cropped camera frame portions are of a form which is suitable for the point of light, produced by the pinpoint light source, that irradiates the object to be photographed. The selectively cropped camera frame portion is preferably subdivided into subdivisions which can be used for a comparison analysis, whereby the properly aligned orientation of the intra-oral camera can be verified.
Further details, advantages, and features of the present invention are described in the hereinafter-following description of an embodiment of the present invention taken with reference to the figures of the drawings.
The picture taking device 12 is a device for obtaining information concerning physical and/or color-related properties of a tooth of a patient. The picture taking device comprises a digital camera (for example, an intra-oral camera). Examples of suitable picture taking devices include the camera Power 0/00, which is manufactured by the Insight Company in San Carlos, Calif., and the Cygenascope brand camera manufactured by Cygnus Instruments, Inc. in Goleta, Calif. A further example of such a camera is the model VistaCam. Such cameras are the type of cameras which can be freely supported in the hand of a user. The cameras typically comprise a display, a storage component, software, and a port for communicate with a personal computer. Such cameras are in the position to capture the light characteristics, the color, the color shade, the type of color, or, as well, the color saturation of the object of interest and to take a picture while taking into consideration such factors. The color can be classified in any suitable desired classification code such as, for example, classified in accordance with RGB, in accordance with L*, a*, b*, or in another suitable desired classified manner.
In another embodiment of the present invention, it is provided that additional properties of the picture or, as well, of the selectively cropped camera frame portions, are captured such as, for example, the focus parameter or the like. Typically, the picture taking device 12 comprises an integrated display such as, for example, an LCD display on the backside of the digital camera.
A user of the intra-oral camera can see a picture of a tooth of a patient via the display device 14. Also, certain software analysis functions can be deployed to provide, for example, color shade analysis. Such captured parameters can, as well, be displayed on the display device. It is provided, in accordance with the present invention, that what is shown in the display device 14 is that which can be seen at that instance in the viewfinder of the camera—that is, that which would be captured in a picture taken by the camera at that instant. In lieu of the digital LCD display of a camera, a computer monitor can also be used which is coupled with a camera such that display information can be transmitted to the computer monitor.
The storage component 16 of the present invention stores, typically, the picture and, additionally, certain picture parameters. For example, color shade information such as, for example, certain color properties of tooth color shades, in accordance with a suitable color shade scheme table, are stored. Additionally, the storage element 16 serves as a buffer. The storage element 16 can be a semiconductor storage or a fixed plate or another suitable storage element such as, for example, a storage element in a computer. It is also possible, apart from the storage of a picture, to use a separate storage element, whereby it is possible to accomplish such storage via media such as a CD or a DVD.
Conventional elements can be deployed to serve as the user interface 18. In this connection, a keyboard, a mouse, a voice recognition system, and the like can be deployed. The user interface 18 permits a user to manipulate the picture taking device 12 in a suitable manner to thereby, for example, take a picture, to select a picture to be deleted, to determine the respective tooth a picture of which is to be taken, or the like.
The processing device 22 is typically a microprocessor or a microcomputer whose software operates for analyzing and identifying teeth color shades and which is available to provide the necessary functions for the taking of a picture. The required elements capable of performing such functions are conventionally available as circuits or, as well, as software. For example, a computer such as a personal computer (PC) can be provided to operate as the processing device 12, whereby it is to be understood that it is also possible to use elements which are conventionally comprised in a personal computer such as storage elements, displays, user interfaces, and communication devices as well as transmission devices to at least partially fulfill the operations of the display device 14, the user interface 18, the storage element 16, the communication device 20, and the output device 24. Separate processors or, as well, combinations of various processors, which are, in part, integrated into the camera and, in part, integrated into the personal computer, can be deployed.
In accordance with the present invention, a device for setting the camera into a proper picture taking position 26 is provided. The device for setting the camera into a proper picture taking position 26 supports the user with respect to the orientation of the picture taking device 22. Several components in the system 10 can be provided in this connection. Such components may comprise a pinpoint light source such as, for example, a laser diode, or a sharp focused light diode. Additionally, the hardware and the software which evaluate the picture information of the light patch produced by the irradiation of the area of interest by the pinpoint light source can also be considered.
The intra-oral camera 10 can be a component of a device for performing a color shade analysis. Such color shade analysis devices are described, for example, in U.S. Pat. No. 6,305,933 B1 and in WO 00/25696, whereby both of these references are fully incorporated by reference herein. It is preferred that a short tube for protection against false light is provided so that the picture that is taken is not contaminated by such false light. A tube of this type is shown, for example,, in U.S. Pat. No. 6,210,159 which is hereby fully incorporated by reference herein.
An example of an intra-oral camera can be seen in
Analyses can be performed in order to determine whether the combination alignment setting and picture taking device 34 is properly aimed toward the object of interest. As desired, other functions can be performed as well such as, for example, an identification of the color shade with reference to a color shade reference table. In accordance with the present invention, the combination alignment setting and picture taking device 34 includes, for supporting the user's picture taking task, a picture taking alignment device for properly orienting the intra-oral camera in its operating position. In this regard, the picture taking alignment device for properly orienting the intra-oral camera in its operating position assures that the combination alignment setting and picture taking device 34 is properly aimed.
In this connection, as seen in
The light source 48 is mounted on the camera at a slight angle of, for example, 1 through 10° relative to the optical axis 49. To compensate for this divergence, the orientation is selected such that, at a given or predetermined spacing between the camera 44 and the tooth surface 46, the optical axis 49 and the light point produced via the light source 48 coincide at an intersection point. It is to be understood that, in this connection, a spacing determination is effected as well which, at the same time, facilitates the focusing of the picture taking device 12 in the camera 44.
In order to, as well, make visually clear for a user, such as, for example, a dentist, the focus operation of this type and, therefore, the establishment of the spacing, it is provided, as can be seen in
It is also possible to use a short tube or another suitable distance retainer which thereafter maintains the spacing following the initial setting thereof. Also, it is possible to undertake a measurement of the lightness via the camera 44, whereupon such a measurement measures the lightness of the produced light point and indicates, upon measuring a maximum lightness value, that the aiming orientation is being performed.
In accordance with step 68, a picture taking alignment device for properly orienting the intra-oral camera in its operating position 26 is provided if the camera is to be substantially properly aimed.
As can be seen in step 70 illustrated in
Of these steps, the steps 62 and 66 are typically performed by the user, while the steps 64, 68, 70, and 72 are, in the preferred embodiment of the invention, automatically performed—that is, are computer-controlled steps.
The aiming is preferably performed such that a limited selectively cropped camera frame portion of the captured picture is evaluated. This is shown in individual detail in
The size of the selectively cropped camera frame portion is dependent upon the light patch and its size and configuration, that is, the light patch being produced by the light sources 48 and 50 on the tooth. In accordance with the present invention, it is, in any event, provided that the selectively cropped camera frame portion captures the entire light patch.
In an advantageous embodiment of the present invention, the selectively cropped camera frame portion is now partitioned into subdivisions which are explained in more detail with reference to
In lieu of the decidedly cost favorable laser diode, it is also possible to deploy a laser which can produce a sharply limited light patch or light point. A laser is, however, substantially more expensive and brings with it only a certain limited value so that the cost favorable light sources are, in contrast, preferable.
As is clearly indicated in step 86, the picture information of the selectively cropped camera frame portion is evaluated in order to determine whether the camera is properly aimed at the object of interest. For example, picture information relating to the color, the shape, and the lightness of the light point produced by the pinpoint light source can be evaluated in order to determine if proper aiming has been accomplished.
In the steps illustrated in
In accordance with step 96, the picture information of the subdivisions is now captured. In this connection, the light parameter of each subdivision is captured, this information then being compared, in step 98, to that of the other subdivisions. According to step 100, it is then determined whether one of these subdivisions is the desired selectively cropped camera frame portion which displays the middle of the tooth.
Also, if the inventive method is deployed with respect to capturing a picture of a complete tooth, it is to be understood, that, in lieu of this, a portion of a tooth can be captured as well and a corresponding evaluation of such can be undertaken.
To evaluate and identify the subdivisions, a comparison can be performed on, for example, the lightness properties of two subdivisions disposed opposite one another. The orientation is then determined as the middle orientation if the lightness values of these opposed two subdivisions agree with one another. This serves to provide the orientation evaluation function, then, so long as the light patch produced by the light sources 48 and 50 exhibits a symmetrical lightness distribution such as, for example, a distribution in accordance with a Gaussian curve.
It is also possible to compare the absolute lightness value of the central subdivision with the lightness value of a relatively more remote subdivision. In a suitable different manner, the symmetry of the lightness can be evaluated, whereby, as well, information can also be captured to determine whether the horizontal-lateral and the vertical lateral subdivisions are each comprised of the same lightness.
As can be seen in the lower portion of
The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.
While a preferred form of this invention has been described above and shown in the accompanying drawings, it should be understood that applicant does not intend to be limited to the particular details described above and illustrated in the accompanying drawings, but intends to be limited only to the scope of the invention as defined by the following claims. In this regard, the term “means for” as used in the claims is intended to include not only the designs illustrated in the drawings of this application and the equivalent designs discussed in the text, but it is also intended to cover other equivalents now known to those skilled in the art, or those equivalents which may become known to those skilled in the art in the future.
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|U.S. Classification||396/16, 348/66, 348/77, 396/281|
|International Classification||A61C19/04, A61B1/24, G03B7/02, A61B5/00|
|Cooperative Classification||A61B1/0676, A61B1/24|
|European Classification||A61B1/06, A61B1/24, A61B1/06R6, A61B1/06R4|
|Apr 8, 2004||AS||Assignment|
Owner name: IVOCLAR VIVADENT AG, LIECHTENSTEIN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KERSCHBAUMER, HARALD;ROHNER, GOTTFRIED;POKORNY, WALTER;REEL/FRAME:015200/0029
Effective date: 20040331
|Mar 9, 2010||FPAY||Fee payment|
Year of fee payment: 4
|Mar 5, 2014||FPAY||Fee payment|
Year of fee payment: 8